We’re still a little put off by the army of Smurf-sized elves that Santa works with in this latest interpretation of Claus’ vast toy-making operation, but they’re nowhere near as creepy as seeing the reindeers’ digital doubles without their hides and fur on.

To make computer-generated creatures move and look as realistic as possible, visual effects artists now recreate almost their entire biology in 3D, including the underlying skeletons and muscular systems. On one hand it ensures that outer layers of skin and fur change form and move properly, but on the other hand it’s turning behind-the-scenes videos like this into short horror films.